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Friday, September 28, 2007

YES -Asteroid Probe's Launched

NASA's Dawn spacecraft in fine health after rocketing into space just after sunrise today, ending a long wait for mission scientists even as the probe's own eight-year journey to two large asteroids is just beginning.

For Dawn principal investigator Chris Russell, the liftoff capped a 15-year effort to plunder the secrets of planetary formation from asteroids Vesta and Ceres. Russell and his mission team watched Dawn rise over its Cape Canaveral Air Force Station in Cape Canaveral, Florida from the spacecraft's Launch Control Center.

"They were very taken by today's launch," said Russell, of the University of California, Los Angeles, of his colleagues in launch control after liftoff. "In fact, my wife cried when she saw it."

NASA first approved Dawn's mission as part of its Discovery program for smaller, more affordable science expeditions in 2001. Russell added that he first envisioned the mission using its efficient ion drive in 1992.

Since then, the mission has survived solar array dings, weather delays, rocket booster and launch tracking issues, as well as cancellation in March 2006. The space agency set the mission's current cost at about $357.5 million, not counting the cost of Dawn's Delta 2 rocket.

Dawn is now headed for a February 2009 swing past Mars before reaching its first space rock target, the bright and rocky asteroid Vesta, in August 2011. The probe's novel Xenon ion propulsion system is expected to guide it into orbit around Vesta for almost a year, then send it off toward the icy dwarf planet Ceres -- the largest space rock in the asteroid belt -- for a February 2015 rendezvous.

"The spacecraft is safe, it is healthy and there's not a single [major] issue aboard," said Keyur Patel, Dawn project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif., after the successful launch.

He credited Dawn's experienced mission team with tackling the last-minute hurdle of a wayward ship that encroached within the launch range perimeter. The snag delayed the probe's liftoff by about 14 minutes, after which the ship moved clear of the launch range in time for a 7:34 a.m. EDT (1134 GMT) space shot.

Dawn's two expansive solar arrays, which measure about 65 feet (about 20 meters) from tip to tip, successfully unfurled after liftoff and its primary science instruments were found to be in good health, mission managers said. A few minor issues, such as a one amp difference in the current produced by the two solar arrays, have popped up, but none are considered serious enough to pose a problem, they added.

"They're all just fine tuning," Patel said.

By Friday morning, Dawn is expected to have flown beyond the orbit of the moon as it continues its outbound flight to the asteroid belt that sits between the orbits of Mars and Jupiter.

Mission managers plan to test its three ion engines within about five days. A series of instrument checks of Dawn's optical camera, mapping spectrometer and gamma ray and neutron detector will also be performed, though the tools won't be fully calibrated until after the Mars flyby, Patel said.

"Every time we launch a spacecraft, they all have their own personalities," Patel said. "And what we're about to discover is what kind of personality Dawn has; whether it's going to be a well-behaved child, or someone that's slightly naughty."

source http://www.msnbc.msn.com/id/21014201/Spacecraft’s ion drive gets its day in the sunDawn asteroid probe puts high-tech propulsion system to toughest test.After suffering its share of dark days, NASA's Dawn mission finally had its “day in the sun” with Thursday morning’s launch toward our solar system's main asteroid belt.

The sun nearly set on Dawn a year and a half ago, when NASA canceled the mission over concerns about its ion engine. After a review of the planned improvements for the spacecraft, the space agency resurrected the project — but that wasn't the end of the mission's setbacks. Its originally scheduled June launch date was ruined by a processing accident involving its booster rocket.

That delay might have been a blessing in disguise, said Dawn mission designer Mark Rayman of NASA’s Jet Propulsion Laboratory

more from NASANASA's Dawn Spacecraft Enroute to Shed Light on Asteroid Belt

CAPE CANAVERAL, Fla. - NASA's Dawn spacecraft is on its way to study a pair of asteroids after lifting off Thursday from the Cape Canaveral Air Force Station at 7:34 a.m. EDT.

Mission controllers at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., received telemetry on schedule at 9:44 a.m. indicating Dawn had achieved proper orientation in space and its massive solar array was generating power from the sun.

"Dawn has risen, and the spacecraft is healthy," said the mission's project manager Keyur Patel of JPL. "About this time tomorrow [Friday morning], we will have passed the moon's orbit."

During the next 80 days, spacecraft controllers will test and calibrate the myriad of spacecraft systems and subsystems, ensuring Dawn is ready for the long journey ahead.

"Dawn will travel back in time by probing deep into the asteroid belt," said Dawn Principal Investigator Christopher Russell, University of California, Los Angeles. "This is a moment the space science community has been waiting for since interplanetary spaceflight became possible."

Dawn's 3-billion-mile odyssey includes exploration of asteroid Vesta in 2011 and the dwarf planet Ceres in 2015. These two icons of the asteroid belt have been witness to much of our solar system's history. By using Dawn's instruments to study both asteroids, scientists more accurately can compare and contrast the two. Dawn's science instrument suite will measure elemental and mineral composition, shape, surface topography, tectonic history, and it will seek water-bearing minerals. In addition, the Dawn spacecraft and how it orbits Vesta and Ceres will be used to measure the celestial bodies' masses and gravity fields.

The spacecraft's engines use a unique, hyper-efficient system called ion propulsion, which uses electricity to ionize xenon to generate thrust. The 12-inch-wide ion thrusters provide less power than conventional engines but can maintain thrust for months at a time.

The management of the Dawn launch was the responsibility of NASA's Kennedy Space Center, Fla. The Delta 2 launch vehicle was provided by United Launch Alliance, Denver.

The Dawn mission to Vesta and Ceres is managed by JPL, a division of the California Institute of Technology, Pasadena, for NASA's Science Mission Directorate, Washington.

The University of California, Los Angeles, is responsible for overall Dawn mission science. Other scientific partners include Los Alamos National Laboratory, N.M.; Max Planck Institute for Solar System Research, Katlenburg, Germany; DLR Institute for Planetary Research, Berlin; Italian National Institute for Astrophysics, Rome; and the Italian Space Agency. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft.